[Tutor] First few eigenvectors of Numeric Array

[Danny Yoo]

On Thu, 2 Sep 2004, Stuart Murdock wrote:

> I have a 10000 by 10000 square Numeric array which I have obtained using
> Numeric python. I need to obtain the first 10 eigenvalues and
> eigenvectors of this so I dont want to have to calculate all
> eigenvectors of the matrix. Is anyone aware of any pythonic packages
> which can calculate, lets say, the 10 eigenvectors corresponding to the
> top 10 eigenvalues of a Numeric array.


Hi Stuart,

Yikes!  *grin*

This sounds like a really specialized question; I'm not sure if many of us
here can help.  You may want to ask this question on the Scientific Python
(SciPy) mailing list:

    http://www.scipy.org/

Isn't Numeric Python now deprecated in favor of the Numarray project,
though?

    http://www.stsci.edu/resources/software_hardware/numarray


Numarray does provide a function to grab eigenvalues and eigenvectors:

    http://stsdas.stsci.edu/numarray/Doc/node64.html

and Numeric Python has similar functions:

    http://www.pfdubois.com/numpy/html2/numpy-18.html#pgfId-303058

but neither appear to allow a 'N max eigenvalues' style query.  I don't
personally have the math background to point out how to make that work.
I'd ask on SciPy, where that community may be better equipped to help.


Best of wishes to you!